Car roof



y 19, 1932- c. D. BONSALL 1,868,191

CAR ROOF Filed Feb. 27, 1951 H 7- TO em: K54

seam caps secured Patented July 19, 1932 V UNITED STATES PATENT FFCHARLES DAVID BONSALL, OF PITTSBURGH, PENNSYLVANIA;.ASSIGNOR T01; H.1mm;

LPI-IY COMPANY, on NEW KENSINGTON, PENNSYLVANIA,

SYLVANIA Application filed February 27, 1931.

level, the side panels being provided with.

upstanding flanges, and the upstanding flanges of adjacent sheets beingstraddled by thereto by horizontally disposed rivets.

In the accompanying drawing which forms part of this specification andwherein like numerals refer to like parts wherever they occur,

Fig. 1 is a plan view of a roof embodying my invention; I

Fig. 2 is a cross-section of a part "of the car roof on the line 2-2 ofig. 1;

Fig. 3 is a longitudinal sectional View on the line 3-3 of Fig. 1;

Fig. 4 is an enlarged cross-sectional detail at the eaves of the car;and g Fig. 5 is an enlarged section through the seam construction.

part of a car The present roof comprises metal sheets 1 I that extendfrom side plate to side plate 2 of the car and have their ends bent downand riveted to the side plates. The individual roof sheets are offsetvertically along longitudinal lines to form a wide middle panel 3 at oneelevation and narrower side panels 4 at a higher elevation, the upperand lower panels being connected continuously by web members 5 whichpreferably decrease in height from a maximum at the ridge to a minimumat each eaves end. Along the side margins of the upper panels areupstanding flanges 6, and the upstanding flanges of adjacent sheets abutagainst each other. Such abutting flanges are straddled by a rebent seamcap 7 whose sides are firmly clamped against the upstanding flanges byhorizontal rivets 8 that extend through said seam cap and said flanges.Preferably the seam caps than would otherwise A ooaroan rro v or PENN-CAR. noon 7 Serial No. 518.705.

are thicker than the sheets and have lateral I" flanges 9 at their loweredges that rest on the marginal portions of the roof sheets. V

It is noted that the present roof is'designed to function as a beamsupported on the side plates, in which case the middle panels of.

the roof sheets are under tensile stress and i the upperpanels are undercompression. In designing such a roof, the capacities of the webmembersan'd of. the compression memher for taking care of thestressesthat tend to buckle them are the principal limiting factors; andin turn, the strengthof the web' against buckling is. dependent. uponits height, and the strength of a compression panel against buckling isdependent upon its width. In the present construction, .the'compressionstrengthof the roof is greatly augmented by the seam construction duenot only to its consisting of the upstanding flanges and the thickrebent seam cap rigidly clamped together but due also to its locationabove the upper level of the roof sheets and consequently at thegreatest distance above the neutral axis. seam cap is further increasedby making it thicker than the sheets and lar section, that is, withlateral flanges'.- Not only does the seam construction itself very theroof considered as a beam,'but s'uch compressive strength is'alsoincreased by making the upper panels of the individualsheets relativelynarrow, such a panel being stiffened on one side by the continuous webwhich joins it to the lower panel and on the other side by the seamconstruction. Theseseveral factors may be varied individually and permitthe webs to be made narrower and consequently more resistant tobuckling. As the roof is thus greatly strengthened against compressionand buckling stresses, it becomes feasible to make the lowerpanels widerbe practicable I for proper beam action; and likewise it becomesfeasible to use sheets of lighter gage than would otherwise bepracticable. v

In practice, it is convenient and desirable to make the side panels of asheet equal to The compression strength of the I of greater depth mldwayof the 'car and by making it'of anguso greatly increase the compressivestrength of the compressive each other and together equal to the middlepanel; but-when the sheets are quite wide or thin, it is preferable tomake narrower and rely on the seam cap to make strength'of the roofcommensurate with the tensile strength of the lower panels.

1 r What-I claimis:

: side portions at a carroof comprising roof sheets rig idlysecuredftogether at 7 between sucl levelsjbeing such that the roof oftheupper portions including the seam coni a structions.

middle portions are I sheets having abutting upstanding flanges 7' alongtheir side margins and seam caps that v i straddle said flanges and arerigidly secured will act as a beam and the'tensile strength ofthe lowerportions being substantially commensurate with the compressive strength2 A car roof comprising a side portions are at one level and whose at alower level, said thereto, the distance between suchlevels being suchthat the roof will act asa beam and said seam 1 caps being thicker thansaid sheets and having .base are adapted to strengthen the roof againstbuckling and eompressionstresses.

3. A car roof comprising roof sheets whose longitudinal middle portionsare at one level and whose side portions are at a higher level, thedistance between such levels beingsuch that the roof will act as a beamand the cross- 7 sectional area of the middle portion of a sheet I beingsubstantially equal the middle portion being at a to the cross-sectionalarea of the two side portions thereof, adjacent sheets being rigidlysecured together by upstandingseams.

' 4. Acar roof-comprising-roofsheets whose 7 side vmargins haveupstandlng flanges that are rigidly secured together flatwise, the sideportions ofeach sheet being at lowerflevel, the distance between suchlevels being such that theroof will act as a tions beingsubstantiallyequal 1n width and their aggreg; equal to the width of themiddle portion.

Signed atNew Kensington,

this 23rd day of Feb, 1931.

V GHARLE S 'DAVID BONSALL. s

the side panels i V their-side edgesby upstandlng' seams, eachsheethaving its-lon 3 i i gitudinal middle portion at one level and its 1higher level, the distance roof sheets whose flanges whereby they onelevel and beam and said side porr te width being a substantially-Pennsylvania,

